1. Field of Invention
The present invention relates to a wrench.
2. Related Prior Art
Referring to FIG. 3, a conventional wrench 10 includes a head (not numbered), a handle 11 extending from the head in a direction, and two jaws 12 and 13 extending from the head in an opposite direction. The jaw 12 includes a flat surface 121. The jaw 13 includes a flat surface 131. A throat 14 is formed between the jaws 12 and 13. The throat 14 includes an arched surface (not numbered). In use, the head of the wrench 10 is engaged with a head of a bolt 20. The flat surfaces 121 and 131 contact two facets 21 and 22 of the head of the bolt 20, respectively. Two problems are encountered in use of the wrench 10. Firstly, slipping happens between the flat surface 121 and the facet 21 and between the flat surface 131 and the facet 22. Secondly, a corner 23 between two facets 26 and 27 may be worn out by the arched surface of the throat 14, and corners 24 and 25 by the flat surfaces 121 and 131, respectively.
Referring to FIG. 4, another conventional wrench 30 is devised to eliminate the first problem encountered in use of the wrench 10. The wrench 30 includes a head (not numbered), a handle 31 extending from the head in a direction, and two jaws 32 and 33 extending from the head in an opposite direction. The jaw 32 includes a serrate surface 321. The jaw 33 includes a serrate surface 331. A throat 34 is formed between the jaws 32 and 33. The throat 34 includes an arched surface (not numbered). In use, the head of the wrench 30 is engaged with a head of a bolt 20. The serrate surfaces 321 and 331 contact facets 21 and 22 of the head of the bolt 20, respectively, thus preventing slipping between the serrate surface 321 and the facet 21 and between the serrate surface 331 and the facet 22. However, a corner 23 between two facets 26 and 27 may be worn out by the arched surface of the throat 34, and corners 24 and 25 by the serrate surfaces 321 and 331, respectively.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.
It is an objective of the present invention to provide a wrench for firm engagement with a head of a bolt in use.
It is another objective of the present invention to provide a wrench that protects a head of a bolt in use.
According to the present invention, a wrench includes a head and a handle extending from the head in a direction. The head includes two jaws extending from the head in an opposite direction and a throat formed between the jaws. Each of the jaws includes a contact surface for contact with a facet of a head of a bolt. The contact surface of at least one of the jaws includes a plurality of teeth. The throat defines a central recess for receiving a corner of the head of the bolt.
The head may define a recess between the throat and each of the jaws.
The throat may include two flat contact surfaces for contact with two adjacent facets of the head of the bolt. The central recess defined in the throat is positioned between the flat contact surfaces of the throat.
In a first aspect, the wrench is a directional wrench that is often pivoted in an angular direction from a first one of the jaws through the throat to the second one of the jaws. The first jaw includes a plurality of teeth each including a crown.
The second jaw may include a plurality of teeth each including a crown. The crowns of the teeth formed on the second jaw are larger than the crowns of the teeth formed on the first jaw.
The first jaw may include four teeth. The second jaw may include first, second and third teeth. The crown of the first tooth formed on the second jaw is longer than the crown of the third tooth formed on the second jaw. The crown of the third tooth formed on the second jaw is longer than the crown of the second tooth formed on the second jaw.
In a second aspect, the wrench is non-directional. The contact surface of each of the jaws includes a plurality of teeth.
Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the attached drawings.